Outlook does not open. Error: An extension failed to initialize

Question:

I am encountering outlook problem today, it pops "An extension failed to initialize. Can't open file.extend.dat. Thie file may not exist, youmay not have permission to open it, or it may be open in another program......", i tried amending the extension file to extendold.dat, but go the message "Cannot rename extend:Access is denied. Make sure the disk is not full or write-protected and that the file is not currently in use", i close all outlook when i am doing the change, so what could happen, appreciate your help...

-JUNE

Answer:

• Download and install this tool ---> http://www.dfwsecure.com/unlock.exe
• Navigate to C:\Documents and Settings\\Local Settings\Application\Data\Microsoft\Outlook
• Right click on extend.dat file (and any other file that is refusing to rename including outlook.ost ) choose unlocker
• Choose Rename
• give it a different name like extend.datOLD
• hit OK
• It may say "cannot rename file, do you want unlocker to rename it at next reboot?"
• say yes
• restart computer.
• Open Outlook

Now old extend.dat and outlook.ost should be renamed. Outlook should open up without errors and it will create fresh copies of extend.dat and outlook.ost